More tropical birds heading to SA
Southern Africa can expect to see more tropical birds in the coming years, as breeding and migration patterns are affected by global warming. This is one of the few positive effects that climate change has on these fragile creatures.
“As with all of Earth’s creatures, birds are being affected by climate change,” said Mark Brown of the University of KwaZulu-Natal’s department of biological and conservation sciences. “Highly sensitive to weather, they are the ‘canaries in the coal mine’, and are responding to current levels of climate change.”
According to Brown, climate change affects birds’ behaviour, distribution and population dynamics, and can result in complete breeding failure.
“We are seeing some changes in migration timing,” said David Allan, curator of birds at the Durban Natural Science Museum. “A lot of birds come down during European winter months, but because of climate change, European winters are becoming warmer and shorter. So we find that birds return to Europe earlier and stay there longer.”
The effect of this is that birds are breeding earlier, and are producing more chicks. “This is positive, as bird populations are increasing,” said Allan. “As habitats shift because of climate change, they can move. In South Africa, we are expecting more tropical birds along the east coast, such as the Red-billed Firefinch.”
But because birds are leaving earlier, they are missing the insect peak, setting their cycles out of sync, and, Brown said, some birds in Europe had stopped migrating.
“Birds also pollinate flowers, and plants are reliant on this,” said Allan. “If the birds disappear, then plants will disappear, and that’s when it will have a big impact on people.”
Other effects of climate change on birds are egg-laying dates, with many American and European species laying eggs up to a month earlier than they did 10 years ago, range shifts, with European species nesting nearly 19km north of where they were a decade ago, and physical changes, with many species expected to become smaller in warmer areas.
“Climate change will also affect birds indirectly by altering their habitats via sea level rise, and changes in vegetation or land use,” said Brown. “For example, Europe’s Mediterranean coastal wetlands, critical habitat for migratory birds, could be completely destroyed by the 2080s.”